Copper base alloys particularly suited for precision resistance



United States Patent Ofifice 3,091,527 Patented May 28, 1963 This invention relates primarily to electrical conduc tive alloys and has for an object the provision of new copper base alloys suitable for forming precision resistors, current-carrying shunts, thermoelectric elements, etc. as used in electrical apparatus of the highest precision.

This application is a continuation-in-part of application Serial No. 632,272, filed January 3, 1957, for Precision Resistance Alloys, now abandoned.

Important requirements of alloys for use in the manufacture of precision electrical resistors and shunts are:

(l) A very high degree of stability of electrical resistance with time;

(2) A very low temperature coefficient of electrical resistance;

(3) In some instances a very low linear temperature coefiicient of electrical resistance;

(4) Predetermined resistivity;

(5) Low thermoelectric power against copper;

(6) Ready attachment to other metals by uniting techniques such as soldering, brazing and cold welding;

(7) Mechanical properties such that the material may be readily drawn into wire, rolled into sheets, etc.; and

(8) Good corrosion resistance.

The alloy which has been most generally used for precision resistors having a low temperature coefficient of resistivity is manganin, an alloy which, as now manufactured, usually consists of manganese, nickel, iron and copper. In fact, manganin has been almost universally adopted for use in precise instruments as most nearly meeting most of the above requirements.

Manganin has only a fair resistance to corrosion under ordinary atmospheric conditions. In order to prevent tarnishing, it has been the practice to protect the surface as by enameling. The electrical characteristics of manganin are readily influenced by its thermal and mechanical history, its surface condition and its chemical composition. Small changes in any one of these factors result in relatively large effects upon its electrical properties.

The manganin alloys do not possess the above characteristics to the extent now needed for the most precise instruments. This is particularly true with respect to its temperature coeflicient as there is an increasing demand for instruments capable of being used over the temperature ranges greater than -50 C. to 70 C. and the aforesaid manganin alloy system is not capable of producing stable alloys with peak temperatures lower than approximately 26 C.

As the temperature is increased, the resistance of manganin first increases and then decreases. The curve of resistance versus temperature is parabolic over a reasonably wide range. The effect of temperature change is least when the mean temperature of use is the temperature of maximum resistance-the peak temperature. Many of the new alloys herein disclosed have the same general type of resistance-temperature characteristic as manganin. By varying the percentages of the constituents, alloys may be made wherein the resistance temperature relationship is either parabolic or linear over a selected temperature range.

The present invention provides precision resistance alloys having low and predetermined temperature coeflicients of resistance, consisting of manganese in the proportions of 2% to 38% by weight, at least three of the following ingredients in any proportions by weight as follows:

and the balance essentially copper, where indium and nickel are never concurrently zero and wherein all of the alloying elements are in solid solution in the copper base. The foregoing constitutes nominal limits of analysis and indicates the nominal constituent content in percent by weight of the finished alloy and not the ingredients in percent by weight compounded to make the alloy.

Within the foregoing broad composition range it has been found that desirable five component alloys having resistivities from about 40 to 50 microhm-centimeters for shunt resistors intended for operation at temperatures in the neighborhood of 40 C. to 60 C. are contained in the more limited range consisting of Manganese 9.1 to 11.1% (by weight). Aluminum 4.2 to 4.4% (by weight). Indium 1.9 to 2.2% (by weight). Iron 0.06 to 0.08% (by weight). Copper Balance (including incidental impurities).

One of the preferred specific alloys in this group is alloy number 1444 listed hereinafter in Table I.

Five component alloy compositions having resistivities from about 50 to microhm-centimeters suited for wirewound resistors intended for operation at ambient temperatures of about 18 C. to 40 C. and within the above broad composition range are contained in the more limited range consisting of Manganese 11.1 to 14.8% (by weight).

Aluminum 4.1 to 4.5% (by weight).

Indium 1.9 to 2.2% (by weight).

Iron 0.05 to 0.11% (by weight).

Copper Balance (including incidental impurities).

Table I Chemical analysis I Electrical properties 2 Alloy Mn, Al, In, Fe, Therm o- Peak percent percent percent percent Resistivity electric B constant temp,

at 25 C. power 0.

v. Cu

B. B4 4.04 1. 99 0. 099 40. 2 +0. 07 2. 6 68. 8. 90 4. 37 1.92 0.066 40.6 +0.09 2. 71. 7 9. 09 4. 37 1.96 0. 086 41. 2 +0.16 2. 0 64.5 9.74 4. 22 1.98 0.077 43.9 +0. 32 2. 8 51. 6 11.05 4. 43 1.05 0.105 48.0 +0. 56 2. 8 39.0 11.58 4. 35 2. 03 0. 062 52.0 +0. 83 3. 8 29. 8 12. 28 4.15 2.16 0.079 52. 8 +0. 90 -4. 0 28. 8 12.56 4.41 2.06 0.082 54. 0 +1.02 4.2 27.0 12. 70 4. 50 1.98 0.067 54. 7 +1.03 4. 5 27.0 12. 67 4. 36 1. 92 0. 057 54. 2 +1.07 -3. 9 26. 8 12.56 4. 16 2.08 0.082 54. 4 +0.97 3. 2 24. 8 13.03 4.12 2.12 0.086 55. 9 +1.07 -4. 2 22. 6 13. 73 4.22 1.92 0.081 59.1 +1.30 4. 7 19.0 14.35 4.26 1.94 0.073 61.4 +1.44 -5. 0 18.8 1447-- 14. 73 4. 28 2.02 0.075 63.2 +1.57 -4. 6 19.5 Good commercial manganin- 48. 6 1. 54 5. 7 27. 4

1 Balance copper plus incidental impurities 1 Units for (1) microhm=cms.; (2) microvolts/ 0.; (3) [(ohms/ohmH" O. 1(]

In above Table I, the electrical properties of columns (1) to (4) were obtained from alloy samples fully annealed and free from oxide. Column (1) gives the specific electrical resistance at C. for each of the alloys expressed in microhm-crn. Column (2) is the thermoelectric power of the alloys against copper expressed in mierovolts per C. over the range of 0 to 50 C.

The resistance-temperature relationship for these alloys may be expressed in the form R =R 1+At+Bt where R is the resistance at temperature 1, R is the resistance at 0 C., and A and B are constants for a given alloy. The temperature coeiiicient at temperature 2 is given by R.,( A+2Bt and the rate of change of the temperature coefficient with temperature is R d2 mg -R0 Column (3) lists values of B for the specified compositions. For practical purposes, the B constants in the table may be considered to be one-half of the rate of change of slope of a one ohm resistor.

Column (4) gives the temperature in C. at which the resistance is a maximum.

It has been found that the electrical effect of a particular element in the complex copper-manganese-aluminumindium-iron matrix is a function of its effect as a binary alloy with copper. The additive nature of the effects of the constituents holds only as long as all of the elements of the alloys are in solid solution.

In comparing the properties of the five-component alloys described above with those of manganin, which has heretofore been considered the best precision resistance alloy, the following is found:

(1) The temperature coetiicient of resistivity is characteristically smaller than that for manganin, as seen from column (3) of Table I.

(2) The resistivity can be controlled to be about the same as that of manganin, as evident from column (1) of Table I.

(3) The electrical stability is at least as good and the initial stabilizing period is shorter than for manganin.

(4) The thermoelectric power against copper is less than that of manganin for alloys in the corresponding peak-temperature range. See columns (2) and (4) of Table I.

(5) The oxidation or tarnishing resistance is considerably better than that of manganin. For example, coils of bare wire exposed to production oven atmospheres for 48 hours at C. were not tarnished while manganin coils exposed in the same manner were considerably darkened. A series of bare coils given five successive 24-hour bakes at 140 C. showed no visible eifects of oxidation.

(6) These five-component alloys are much more readily brazed but slightly less easy to solder than manganin.

(7) They are as easy to fabricate as manganin.

By adding nickel as a sixth component to the fivecomponent matrix, it was found that the electrical properties could be further improved without sacrificing any of the desirable properties of the five-component alloys.

Within the foregoing broad composition range, it has been found that desirable six-component alloys having resistivities of about 45 microhm-centimeters for shunt resistors intended for operation at temperatures in the neighborhood of 40 C. to 60 C. are contained in the more limited range consisting of:

Percent by weight Manganese 9.4 to 10.2. Aluminum 4.2 to 4.4. Indium 1.9 to 2.1. Nickel 1.6 to 1.8. Iron 0.06 to 0.08. Copper Balance (including incidental impurities).

One of the preferred specific alloys in this group is alloy number 1493 listed hereinafter in Table II.

Six-component alloys having resistivities of from about 45 to 60 microhm-centimeters suited for use in the manufacture of wire-wound resistors intended for operation at ambient temperatures of about 10 C. to 40 C. are contained in the more limited range consisting of:

Percent by weight Manganese 10.8 to 14.7. Aluminum 4.2 to 4.4.

Indium 1.8 to 2.1.

Nickel 1.6 to 3.1.

Iron 0.06 to 0.30.

Copper Balance (including incidental impurities).

lit

Table II Chemical analysis 1 Electrical properties 1 Alloy Mn, t .41, t In, t Ni, t Fe, t R ti 1 Thernnio- P k percen pereen percen percen peroen es s V1 y e co r e ea at 25 0. power B constant temp, C.

v. Cu

9. 49 4. 38 1. 93 1. 69 0. 068 44. 0. 17 2. 4 63. 6 10. 09 4. 29 1. 92 1. 7? 0. 072 45. 1 +0. 02 2. 9 48. 1 10. 77 4. 35 2. 02 1. 19 0. 064 48. 0. 10 3. 8 31. l) 10. 92 4. 2. 00 1. 63 0. 075 49. 1 -0. 02 2. 8 29. 3 11.11 4.30 1. 96 2. 08 0.078 49. 3 +0.04 3. 6 31. 9 11.13 4. 1.98 1.69 0.071 50. 0 0. 12 3. 3 29. 6 11.15 4. 30 1. 83 1v 66 0. 065 49. 8 +0. 03 3. 8 31.0 11. 20 4. 26 1. 88 1. 64 0. 068 49. 6 +0. 08 4. 2 27. 8 11.79 4. 33 1. 95 1.70 0. 068 52. 3 +0. 28 3. 7 26. 4 12. 18 4. 32 1. 89 1. 72 0. 072 52. 5 +0. 48 4. 3 27. 4 12. 57 4. 30 1. 94 1. 76 D. 070 53. 6 +0.59 3. 7 26. l 12. 4. 34 1. 96 0.82 0. 071 52. 3 +0. 87 4. 8 24. 3 12. 60 4. 31 1. 98 1. 29 9. 074 53. 3 +0. 72 3. 7 22. 9 12.64 4. 31 1.92 1. 52 0. 068 53. 6 +0. 68 4. 0 23.1 12. 61 4.32 2. 02 2. 01 0. 068 54. 2 +0. 54 3.4 31. 7 12. 67 4. 29 1.95 2. 56 0. 071 55. 0 +0. 43 4. 8 34. 6 12. 69 4. 26 1.98 3. 05 0.069 55. 8 +0. 31 4.1 43. 8 12. 4. 28 1.05 1.66 0v 149 55. 4 +0. 49 4. l 22. 6 12. 70 4. 23 1.95 1. 68 0. 242 55.1 +0. 44 3. 6 21. 5 12. 72 4.33 1.98 1. G5 0. 171 55. 9 +0. 49 3. 6 20.8 13. 07 4. 33 1.9? 1. 66 0. 073 55. 4 +0. 75 4. 2 22. 6 14. 10 4. 35 1. 1.67 0.070 59.1 i0. 97 5. 0 21.1 14. 2S 4. 30 0 1. 72 0.071 61. 0 0. 86 4. 5 19. 3 14. 60 4. 29 l. 96 1. 69 0. 067 60. 0 +0. 84 -4. 2 16. 7 14. 53 4. 21 1. 86 1.68 0.117 60.7 +0. 84 5. 3 l5. 7 14. 56 4. 23 1.89 1. 67 0.168 01.0 +1. 06 5. 3 15. 3 14.56 4. 24 1. 92 1. 69 0. 222 81. 0 +0. 68 4. 5 13. 4 1607 14. 25 4. 25 1. 87 1. 09 0.281 59. 9 +0. 54 4. 8 10.5 Good commercial manganin 58. 6 154 5. 7 27. 4

1 Balance copper plus incidental impurities. 9 Same units as for Table I.

The six-component alloys compare with the manganin alloys and the foregoing fivecomponent alloys in the following manner:

(1) The stability of the electrical properties with time is of the same order as that of the best selected manganin which, under favorable conditions, changes in resistance less than 0.005% per year.

(2) The temperature coeflicient of resistivity is smaller than that of manganin or the five-component alloys. See column (3) of Tables I and II.

(3) The peak temperature may be controlled more readily than for either the manganin or the five-component alloy system's.

(4) The resistivity can be controlled to be about the same as that of manganin. See column (I) of Table II.

(5) The thermoelectric power against copper is very small, being, in magnitude, about one-third that of manganin for the same peak temperature. See column (2) of Table II.

(6) The oxidation or tarnish resistance is very high. The six-component alloys do not show discoloration, even after brazing.

(7) Soldering is accomplished with substantially the same ease as with manganin and brazing is much easier. It is now possible to braze smaller wire sizes than has been possible with manganin, thus eliminating soldered joints which are sometimes a cause of instability.

(8) They are as easy to fabricate as manganin.

For most instrumentation purposes it has been found that one of the best alloys of either the five-component or six-component types is the alloy identified above in Table II as No. 1440. This alloy is composed of 10.92% manganese, 4.30% aluminum, 2.00% indium, 1.63% nickel, 0.075% iron and the balance essentially copper. The stability of this alloy is excellent and its temperature coefiicient of resistivity is less than half of that of the best grade of manganin while its resistivity is about the same as that of manganin. The thermoelectric power versus copper is substantially zero {-0.024 microvolt per C.) and the peak temperature of 293 C. is satisfactory for many purposes.

The improvements in electrical properties over those of manganin are of substantial importance. In addition to the negligible thermoelectric power against copper, the

very small temperature cocfiicient permits deemphasis of the importance now placed upon the efiect of small changes in ambient temperature upon accuracy of instruments. These properties make less necessary the matching of resistors for temperature coeilicient and thermal lagging of ratio coils. Superior instruments can be provided without increase in cost, and instruments of higher precision are made possible.

In view of the fact that present-day chemical analytical techniques sometimes result in allowable variation between a plurality of chemical analyses of the same alloy, it has been found that the electrical properties of an alloy are useful in checking the chemical analysis of the alloy. For example, in Table 11, the alloy No. 1440 may be identified either from its chemical analysis or from its electrical properties. Thus, alloy No. 1440 may be defined as an alloy comprising 10.92% manganese, 4.30% aluminum, 2.00% indium, 1.63% nickel, 0.075% iron and the balance essentially copper. Alternatively, alloy No. 1440 may be defined as a copper base alloy including manganese, aluminum, indium, nickel and iron and having the electrical properties as set forth in columns (l)-(4) in Table II. The particular combination of the aforesaid electrical properties of any of the alloys comprised of the foregoing elements uniquely identifies the percentage composition of these elements in the alloy.

It has been discovered that by further varying the percent by weight at the constituent alloys Within limits indicated in the following Tables III to VII that alloys may be made having desirable characteristics other than those set forth in the preceding Tables I and II where the resistivities range from 40 to 63 microhm-centirneters at 25 C., with a parabolic temperature versus resistance relationship and with peak temperatures in the range 10 to 72 C.

With respect to resistivity, there are shown in Table III alloys having resistivities above and below those set forth in Tables I and II. For example, the range is from about 16 to 106 microhrn-centimeters. Additionally, it is to be noted that Table III shows specific examples of alloys 2285-2289 and 2219-2223 having relatively low temperature coeflicients of resistance. It is also to be noted these alloys have substantially linear resistance versus temperature relationships over the range of about 0 C. to C.

For example alloys 2219-21 of Table III have much lower resistivities than manganin and have the desirable physical properties set forth above for the 1440 alloy. The properties of this group of alloys make them parresistivities, flat parabolic resistance versus temperature relationships, low thermoelectric power versus copper, and peak temperatures considerably lower than those of manganin are obtainable.

Table III Chemical analysis Electrical properties Alloy Mn, A], In, Ni, Fe Thermo- Temp. Peak percent percent percent percent pcrce ut Resistivity electric eoellicient temp,

at 25 0. power of resistance C.

v. Cu

2. 00 2. 00 2. 00 2. 00 0. 1O 16. 00 3. 07 3. 1 None 2. 00 2. 00 2. (10 2. 00 0. 16. 90 3. 90 2. 8 None 2. 00 2. 00 2.00 2. 00 0.20 17. 53 4. 17 2. 7 None 2. 00 2. 00 2v 00 2. 00 0. 17. 74 4. 23 2. 7 None 2. 00 2. 00 2. 00 2. 00 0. 17. 80 4. 33 2. 8 None 2. 15 1. 87 2. 24 1. 66 0. 10 16. 00 3. 00 3. 0 None 3. 27 1. 80 2. 23 1. 58 0. 07 19. 32 2. 09 1. 9 None 4. 24 1.77 2. 14 1. 65 0.07 22. 75 -2. 03 1. 2 None 6. 30 1. 90 1. 95 2. 74 0. 13 30.58 2. 03 .39 None 7.18 1. 82 1. 85 2. 78 0. 12 33. 71 1. 77 18 None B. con.

1 Balance copper plus incidental impurities.

9 Units for (1) microhm-cms.; (2) mierovolts/C.; (3) [(ohms/ohru)! C.] 10- units for (5) [(ohrns/ohml 0.)]

X101 Nominal analyses.

ticularly useful for making wire-wound slidewires having more convolutions per unit length hence providing a finer degree of adjustment. Alloys 222224 of Table III are useful for slidewires having a degree of adjustability intermediate those made of the 2219-21 alloys and commercial manganin. The 2212-15 alloys of Table 111 show that primarily by increasing manganese to still higher values, with appropriate adjustments of the other constituents, that desirable resistance alloys having higher In Table IV there is shown a large group of alloys having resistivities in the range 85 to 113 microhm-centimeters and peak temperatures in the range from about 12 C. to 56 C. This shows that alloys having uniformly low temperature coefficients of the same order of magnitude as commercial manganin over a wide range of resistivities can be made to peak at almost any desired temperature over an extended range.

Table I V Chemical analysis 1 Electrical properties I Alloy Mn, Al, 11, Ni, Fe,

percent percent percent percent percent. Thermo- Temp. Peak Resistivity electric eoefilcient temp, at 25 C. power ofresistaucc C.

v. Cu

2 Same units as for Table I.

Table V shows a group of alloys similar to those shown istics of the lower resistivity alloys of Table IV. Of this above in Table IV but additionally containing indium. group the 2185 alloy is particularly good for use in high The resistivities range from about 96 to 109 microhrnresistance value resistors employed where the ambient centimeters. It is to be noted that this group of alloys temperature will vary over a wide range.

Table VI Chemical analysis 1 Electrical properties I Alloy Mn, Al, In, Ni, Fe, Thermo- Temp. Peak percent percent percent percent percent Resistivity electric coefileient temp,

at 0. power oiresistanee C.

v Cu

1 Balance copper plus incidental impurities. Same units as ior Table I.

have, the more desu'able, flatter parabohc resistance versus Table VII sets forth the composition and charactertemperature characteristic, and reduced thermoelectric 1st1cs of a group of h1gl1 resistlvity alloys in the range power agamst copper, and have peak temperatures 111 the from about 130 to 143 microhm-centimeters wl'uch alloys range from about 2 C. to 44 C. have parabolic temperature versus resistance relation- Table V Chemical analysis 1 Electrical Properties 2 Alloy Mu, per- Al. per- In, per- Ni, per- Fe, per- Thermo- Ternp. co- Peak cent cent cent cent cent Resistivity electric efllcient of temp.,

at 25 0. power resistance C.

v. Cu

26. 91 2. 43 0. 3s 6. 04 0. 31 107. 50 +1. 82 -4. 7 2. 6 26.78 2. 45 0. 6. 0s 0. 31 10s. 06 +1.81 -4. 7 4. 9 20. 90 2. 44 0. s5 6. 00 0. 31 107. +1.7 -4. 9 6. 6 26. 32 2. 58 1.41 0. 02 0. 31 107. 58 +1.79 -4. 7 9. 7 26. 79 2. 46 1. 63 0. 04 0. 21 103. 23 +1.81 4. 6 1s. 7 26. 92 2. 31 2. 07 6. 02 0. 30 106. 30 +1. 4. 9 44. 3 23. 70 2. 29 0. 34 6.00 0. 32 90. 00 +1.26 4. 7 s. 7 24. 35 2. 26 0. 93 6. 01 0. 32 93. 77 +1. 33 -4. s 10. 7 24. 63 2. 27 0. s5 6. 04 0. 31 100. 60 7 +1. 43 -4. 9 7. 7 24. 92 2.30 1. 11 6. 05 0. 32 103.31 +1. 50 4. 9 7. 5 25. 83 2. 24 0. s9 6. 03 0. 33 105. 67 +1. 03 -4. 9 s. 3 25. 00 2. 25 0. 6. 00 0. 01 99.16 +1. 95 -5. 2 17. 4 25. 00 2. 25 0. 75 6. 00 0. 05 100. 25 +1.79 5. 1 15. 4 25. 00 2. 25 0. 75 6. 00 0. 10 100. 25 +1. 72 -5. 1 16. 0 25. 00 2. 25 0. 75 6. 00 0. 15 101. 12 +1. 64 -5. 1 15. 6 25. 00 2. 25 0. 75 6. 00 0. 20 101. 23 +1. 63 -4. s 9. 6 25. 00 2. 25 0. 75 0. 00 0. 25 101.77 +1. 60 -4. 9 7. 7

1 Balance copper plus incidental impurities. I Same units as for Table I. 3 Nominal Analyses.

In Table VI there is set forth a group of alloys having ships which are flatter than the comparable lower rerelatively high resistivities ranging from about 112. to sistivity alloys set forth in Table V. Of this group the 144 michrohm-centimeters and the desirable character- 2240 alloy is especially good for use in high resistance value, wire-wound resistors, employed where the ambient temperature will vary over a Wide range.

Table VII Chemical analysis 1 Electrical properties I Alloy Mn, Al, In, Ni, Fe, Thermo Temp. Peak percent percent percent percent percent Resistivity electric eoelfieient temp,

at 25 0. power otresistance C.

v. Cu

34. 91 1. 41 0.33 12. 02 0.30 131.61 +1.76 4. 8 21. 4 34. 49 1.51 0. 62 12. 02 0. 30 132. 23 +1. 76 4. 9 27. 8 34.39 1. 55 0. 85 12.01 0. 36 132. 66 +1.75 4. 8 33. 8 34. 22 1. 33 1.09 12.19 0.34 132. [)6 +1.65 4. 8 9. 3 37. 79 1. 56 0.35 12.00 0. 27 140.80 +1. 93 4. 12.3 37. 96 1. 56 0. 46 12.05 0.27 141. 68 +1 88 4. 5 17. 8 37. 92 1. 52 0. 43 12.06 0.14 141. 81 +2 4. 8 28. 9 37. 86 1. 60 0.43 12.12 0. 29 142. 41 +1 99 4. 8 24. 6 37. 70 1.42 0. 56 12.31 0. 36 142.74 +1 92 4. 6 15.1 34. 80 l. 45 0.52 11.05 0.33 132.16 +1 80 4. 5 9. 4 35. 07 1. 48 0.50 11.97 0. 22 132. 33 +1 80 4. 8 37. 8 35.04 1. 50 0.53 11.95 (1. 24 132. 90 +1.73 4. 9 42. 9 35. 09 1. 47 0. 51 12.00 (1. 34 133. 48 +1. 70 4. 4 7. 1 35.71 1. 49 0.45 11.17 0. 135. 42 +1.93 -4. 5 15. 0 35. T8 1. 49 0.48 12. 08 0.31 133. 73 +1.74 4. 9 41.0 35.99 1. 50 D. 45 12.00 0.26 134. 91 +1. 85 4. 9 35. 6 35. 89 1. 40 D. 45 12. 12 0. 131. 90 +1. 72 4. 8 37. 4 35. 91 1. 50 0. 45 12. 06 0. 135. 91 +1.76 4. 7 24. 3 35. 83 1.42 0. 48 12. 08 0. 44 134. 91 +1.74 4. 7 23. 6 38.0 (1. 5 0.20 14. 9 (1. 20 139.00 +1. 66 5. 4 17. 2 38.0 0.5 0. 25 14. 9 0.20 140. 41 +1. 65 4. 9 11. G 38.0 0.5 0.30 14. 9 0.20 140.26 +1.7 4. 8 9. 6 38. 0 0. 5 0. 20 14. 9 0.25 140. 37 +1. 68 5. 0 ll. 1 38. 0 0. 5 0. 20 14. 9 0.30 140. 20 +1. 60 5. 2 11. 4 38.0 0. 5 0. 20 14. 9 0.35 141.11 +1 58 5. 1 3. 2

1 Balance copper plus incidental impurities 5 Nominal analyses.

For purposes of brevity in the claims, the term resistance alloy is used generically and is intended to include resistors, resistance elements, shunt resistors thermoelectric elements and any alloy for use wherein one or more of the above described desirable qualities of the alloy is applicable. In the claims it is to be understood that the specified percentages of the elements of the chemical compositions are intended to encompass the allowable range of variation by chemical analytical techniques.

It shall be understood that the invention is not limited to the specific embodiments described and that changes and modifications may be made Within the scope of the appended claims.

What is claimed is:

1. A precision resistance alloy having a low temperature coefficient of resistance composed of the following ingredients in the following proportions:

Percent by weight and the balance copper and incidental impurities.

2. A precision resistance alloy having a low temperature coefficient of resistance composed of the following ingredients in the following proportions:

Percent by weight Manganese 10.09 Aluminum 4.29 Indium 1.92 Nickel 1.77 Iron 0.072

and the balance copper and incidental impurities.

ingredients in the following proportions:

Percent by weight 40 Manganese 14.25 Aluminum 4.25 Indium 1.87 Nickel 1.69 Iron 0.281

and the balance copper and incidental impurities.

4. A precision resistance alloy having a low temperature coefficient of resistance composed of the following ingredients in the following proportions:

Percent by weight Manganese 9.74 Aluminum 4.22 Indium 1.98 Iron 0.077

and the balance copper and incidental impurities.

5. A precision resistance alloy having a low temperature coefiicient of resistance composed of the following ingredients in the following proportions:

and the balance copper and incidental impurities.

6. An electrical resistance element formed from a copper base alloy consisting, in addition to copper, of:

Percent by weight Manganese 8.84 to 14.73 Aluminum 4.04 to 4.50 Indium 1.92 to 2.16 Iron 0.057 to 0.105

7. A copper base alloy having low resistivity and suited for use in wire wound slidewires consisting, in addition to copper, of:

Percent by weight Manganese 2.15 to 4.24 Aluminum 1.77 to 1.87 Indium 2.14 to 2.24 Nickel 1.58 to 1.66 Iron 0.07 to 0.10

8. A copper base alloy suited for use as wire wound slidewires consisting, in addition to copper, of:

Percent by weight Manganese 6.30 to 8.40 Aluminum 1.82 to 1.96 Indium 1.85 to 1.95 Nickel 2.74 to 2.78 Iron 0.05 to 0.13

9. A copper base alloy suited for use in high resistance value resistors where the ambient temperature may vary over a wide range composed of the following ingredients in the following proportions:

Percent by weight Manganese 38.79 Aluminum 1.58 Nickel 14.98 Iron 0.22

and the balance copper and incidental impurities.

10. A copper base alloy having high resistance value and suited for use as a wire wound resistor where the ambient temperature may vary over a wide range composed of the following ingredients in the following proportions:

Percent by weight Manganese 34.22 Aluminum 1.33 Indium 1.09 Nickel 12.19 Iron 0.34

and the balance copper and incidental impurities.

11. A copper base alloy suited for use as an electrical resistance element consisting, in addition to copper. of:

Percent by weight Manganese 9.49 to 14.60 Aluminum 4.21 to 4.40 Nickel 0.82 to 3.05 Iron 0.064 to 0.281

Percent by Weight Manganese 8 to 15 Aluminum 4 t0 5 Iron 0.05 to 0.3

and at least one of the other elements of the group consisting of indium up to 3% by weight and nickel up to 4% by weight.

13. A copper base alloy suited for use as an electrical resistance element consisting, in addition to copper, of:

Percent by weight Manganese 2 to 38 Aluminum 0.5 to 5 Indium 0.2 to 3 Nickel 0.8 to 15 Iron 0.01 to 0.05

14. A copper base alloy suited for use as an electrical resistance element consisting, in addition to copper of:

Percent by weight Manganese 22 to 38.79 Aluminum 0.01 to 2.3 Nickel 4.9 to 15.01 Iron 0.01 to 0.5

References Cited in the file of this patent UNITED STATES PATENTS 1,718,502 Vaders June 25, 1929 1,896,193 Corson Feb 7, 1933 FOREIGN PATENTS 414,748 Great Britain Aug. 13, 1934 

1. A PRECISION RESISTANCE ALLOY HAVING A LOW TEMPERATURE COEFFICIENT OF RESISTANCE COMPOSED OF THE FOLLOWING INGREDIENTS IN THE FOLLOWING PROPORTIONS: 